Selection of acknowledgment timing in wireless communications

ABSTRACT

Disclosed is a method including communicating, by a mobile device, with a base station via first and second component carriers having different frequency bands and time division duplexing (TDD) configurations. The method may include receiving one or more downlink transmissions via the second component carrier. The method may include selecting a hybrid automatic repeat request (HARQ) timing sequence based on the TDD configurations of the first and second component carriers. The method may include transmitting one or more positive acknowledgment and/or negative acknowledgement (ACK/NACK) signals, associated with the one or more downlink transmissions, according to the selected HARQ timing sequence. Other embodiments may be described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/997,971, filed Jun. 25, 2013, entitled “SELECTION OFACKNOWLEDGMENT TIMING IN WIRELESS COMMUNICATIONS,” which is a nationalphase entry under 35 U.S.C. §371 of International Application No.PCT/US2012/031040, filed Mar. 28, 2012, entitled “SELECTION OFACKNOWLEDGMENT TIMING IN WIRELESS COMMUNICATIONS”, which designates theUnited States of America, and which claims priority to U.S. ProvisionalPatent Application No. 61/556,109, filed Nov. 4, 2011, entitled“ADVANCED WIRELESS COMMUNICATION SYSTEMS AND TECHNIQUES,” the entirecontents and disclosures of which are hereby incorporated by referencein their entireties.

FIELD

Embodiments of the present invention relate generally to the field ofcommunications, and more particularly, to selection of acknowledgementtiming in wireless communication networks.

BACKGROUND INFORMATION

A time division duplex (TDD) system, in wireless communications, mayoffer flexibility in resource utilization. For example, a TDD system mayuse different TDD configurations to match uplink and downlink trafficcharacteristics of a wireless communications cell. The flexibility ofusing different TDD configurations, may permit the ratio betweenavailable uplink (UL) and downlink (DL) resources to range from 3 UL:2DL to 1 UL:9 DL.

Release 10, of 3^(rd) Generation Partnership Project's (3GPP) long termevolution-advanced (LTE-A) communications standard, may limit support ofthe aggregation of TDD Component Carriers (CCs) to the sameuplink/downlink (UL/DL) TDD configurations. While such limitations mayhave simplified the design and operation within the standard, suchlimitation may have limited potential for greater data throughput.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings inwhich like reference numerals refer to similar elements.

FIG. 1 schematically illustrates a wireless communication network inaccordance with various embodiments.

FIG. 2 schematically illustrates an optional HARQ signal schedulingdiagram in accordance with various embodiments.

FIG. 3 schematically illustrates an optional HARQ signal schedulingdiagram in accordance with various embodiments.

FIG. 4 is a flowchart illustrating selection of an HARQ signalscheduling configuration in accordance with various embodiments.

FIG. 5 schematically depicts an example of selecting a HARQ signalscheduling configuration in accordance with various embodiments.

FIG. 6 schematically illustrates an example of HARQ signal scheduling inaccordance with various embodiments.

FIG. 7 is a flowchart illustrating selection of HARQ signal schedulingfor downlink subframes in accordance with various embodiments.

FIG. 8 schematically illustrates an example of an HARQ signal schedulingdiagram in accordance with various embodiments.

FIG. 9 schematically illustrates an example of an HARQ signal schedulingdiagram in accordance with various embodiments.

FIG. 10 schematically depicts an example system in accordance withvarious embodiments.

DESCRIPTION OF THE EMBODIMENTS

Illustrative embodiments of the present disclosure include, but are notlimited to, methods, systems, and apparatuses for selection ofacknowledgement signal timing in a wireless communication network.

Various aspects of the illustrative embodiments will be described usingterms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that some alternate embodimentsmay be practiced using with portions of the described aspects. Forpurposes of explanation, specific numbers, materials, and configurationsare set forth in order to provide a thorough understanding of theillustrative embodiments. However, it will be apparent to one skilled inthe art that alternate embodiments may be practiced without the specificdetails. In other instances, well-known features are omitted orsimplified in order to not obscure the illustrative embodiments.

Further, various operations will be described as multiple discreteoperations, in turn, in a manner that is most helpful in understandingthe illustrative embodiments; however, the order of description shouldnot be construed as to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

The phrase “in one embodiment” is used repeatedly. The phrase generallydoes not refer to the same embodiment; however, it may. The terms“comprising,” “having,” and “including” are synonymous, unless thecontext dictates otherwise. The phrase “A/B” means “A or B”. The phrase“A and/or B” means “(A), (B), or (A and B)”. The phrase “at least one ofA, B and C” means “(A), (B), (C), (A and B), (A and C), (B and C) or (A,B and C)”. The phrase “(A) B” means “(B) or (A B)”, that is, A isoptional.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a wide variety of alternate and/or equivalent implementations maybe substituted for the specific embodiments shown and described, withoutdeparting from the scope of the embodiments of the present disclosure.This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat the embodiments of the present disclosure be limited only by theclaims and the equivalents thereof.

As used herein, the term “module” may refer to, be part of, or includean Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group) and/or memory(shared, dedicated, or group) that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablecomponents that provide the described functionality.

FIG. 1 schematically illustrates a wireless communication network 100 inaccordance with various embodiments. Wireless communication network 100(hereinafter “network 100”) may be an access network of a 3rd GenerationPartnership Project (3GPP) long-term evolution (LTE) network such asevolved universal mobile telecommunication system (UMTS) terrestrialradio access network (E-UTRAN). The network 100 may include a basestation, e.g., enhanced node base station (eNB) 104, configured towirelessly communicate with a mobile device or terminal, e.g., userequipment (UE) 108. While embodiments of the present invention aredescribed with reference to an LTE network, some embodiments may be usedwith other types of wireless access networks.

eNB 104 may include a receiver module 120 with which to receive signalsfrom UE 108 via one or more antennas 130. eNB 104 may include atransmitter module 124 with which to transmit signals to UE 108 via oneor more antennas 130. eNB 104 may also include a processor module 128coupled between receiver module 120 and transmitter module 124 andconfigured to encode and decode information communicated by the signals.

In embodiments in which the UE 108 is capable of utilizing carrieraggregation (CA), a number of component carriers (CCs) may be aggregatedfor communication between the eNB 104 and the UE 108. In an initialconnection establishment, the UE 108 may connect with a primary servingcell (Pcell) of the eNB 104 utilizing a primary CC. This connection maybe used for various functions such as security, mobility, configuration,etc. Subsequently, the UE 108 may connect with one or more secondaryserving cells (Scells) of the eNB 104 utilizing one or more secondaryCCs. These connections may be used to provide additional radioresources.

Each CC may support a number of communication channels according to arelease of the 3GPP LTE-advanced communication standard. For example,each CC may support a physical downlink shared channel (PDSCH) fortransmission of downlink data. As another example, each CC may supportphysical uplink control channel (PUCCH) or/and physical uplink sharedchannel (PUSCH) to carry information between UE 108 and eNB 104. A CCmay include a plurality of uplink and downlink subframes for carryinginformation between eNB 104 and UE 108. A single 10 ms radio frame mayinclude ten subframes.

The CCs may be configured to transport information according to a timedomain duplexing (TDD) communication protocol. Each CC may be scheduledto transport data to UE 108 or transport data to eNB 104 according toone of several TDD configurations. For example, with reference to Table1, each CC may be assigned to transport data

TABLE 1 TDD Uplink-Downlink Configurations Uplink-downlinkDownlink-to-Uplink Subframe number configuration Switch-pointperiodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D S UU D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  D S U U U D D D D D 410 ms  D S U U D D D D D D 5 10 ms  D S U D D D D D D D 6 5 ms D S U U UD S U U Dand/or control signals according to one of TDD configurations 0-6. Aprimary CC and secondary CC may both be configured with the same TDDconfiguration, or with different TDD configurations. In general, each ofsubframes 0-9 that is labeled with a “D” or an “S” is a subframe withwhich UE 108 receives data from eNB 104, and each of subframes 0-9 thatis labeled with a “U” is a subframe through which UE 108 transmits datato eNB 104.

eNB 104 may be configured to communicate some information solely by thePCell and be configured to communicate other information by either thePCell or the SCell. For example, eNB 104 may be configured to receiveacknowledgment signals from UE 108 solely through the PCell. Accordingone embodiment, the acknowledgment signals may be hybrid adaptive repeatand request (HARD) signals corresponding to a positive acknowledgment(ACK) of receipt of data and a negative acknowledgment (NACK) of receiptof data. In embodiments, UE 108 may be configured to transmit ACK/NACKsignals to notify eNB 104 that transmitted data has or has not beenreceived.

UE 108 may be configured to determine a schedule with which to transmitACK/NACK signals to eNB 104. UE 108 may include a receiver module 144, atransmitter module 148, a processor module 152, and one or more suitableantennas 156. Receiver module 144 and transmitter module 148 may becoupled to one or more suitable antennas 156 to transmit and receivewireless signals to/from eNB 104.

Processor module 152 may be coupled to receiver module 144 andtransmitter module 148 and be configured to decode and encodeinformation transmitted in signals communicated between the UE 108 andthe eNB 104. Processor module may include a communication module 154 andan HARQ module 158. Processor module 152 may be configured to usecommunication module 154 to transmit information in uplink subframes ofthe PCell, e.g., on CC_0, according to the scheduling of a first TDDconfiguration at a first frequency. Processor module 152 may also beconfigured to transmit information in uplink subframes of the SCell,e.g., on CC_1, according to a second TDD configuration at a secondfrequency that is different from the first frequency. According to oneembodiment, the difference between transmission frequencies of CC_0 andCC_1 may range from hundreds of kilohertz to tens of Gigahertz, inaccordance with inter-band carrier aggregation.

As will be described in more detail hereafter, processor module 152 maybe configured to selectively transmit ACK/NACK information for SCellcommunications via a schedule of a TDD UL-DL configuration that isdifferent than the TDD configuration of SCell. In embodiments, processormodule 152 may use HARQ module 158 to select HARQ timing sequence ortiming schedule based on one of the TDD configurations. HARQ module 158may also generate the ACK/NACK information for processor module 152. TheHARQ module may be coupled to the communication module 154 and may beconfigured to use the communication module 154 to transmit the generatedACK/NACK information via the selected HARQ timing sequence.

Various embodiments of the present disclosure may enable a eNB toschedule uplink and downlink data transmission with different TDDconfigurations on component carriers. These features may advantageouslyenable a communication system to transmit data information with higherpeak data rates than previous communication systems. However, someinformation transmitted with a PCell and an SCell having different TDDconfigurations may result in HARQ ACK/NACK resources conflicts. Forexample, because HARQ ACK/NACK signals for both SCell and PCell may betransmitted between UE 108 and eNB 104 solely via uplink subframes ofPCell, uplink subframe schedules of PCell may result in schedulingconflicts for ACK/NACK information for SCell.

While many embodiments described herein, are described in a carrieraggregation context, it will be understood that other embodiments may beapplicable to an embodiment in which the UE 108 and eNB 104 utilize asingle serving cell, with a single component carrier, forcommunications. In these embodiments, the UE 108 may be configured,e.g., by receipt of system information block 1 (SIB1) broadcast by theeNB 104, to communicate data with the eNB 104 according to a first TDDUL-DL configuration. The UE 108 may be further configured to transmitACK/NACK information via a HARQ timing sequence of a second TDD UL-DLconfiguration. These and other embodiments will be described in furtherdetail.

FIG. 2 illustrates a diagram of HARQ ACK/NACK signal scheduling that maybe performed by processor module 152, according to embodiments. FIG. 2shows PCell configured with TDD configuration 1 (shown in Table 1), andSCell configured with TDD configuration 3. Each of lines 200 represent alink between downlink or special subframe data and the uplink subframethat is designated to carry corresponding ACK/NACK information back toan eNB.

According to the solution of FIG. 2, PDSCH HARQ timing on all secondaryserving cells (e.g., SCells) may follow the TDD UL-DL configuration ofthe PCell to allow increased reuse of Rel-10 TDD intra-band carrieraggregation design. For example, HARQ ACK/NACK information for SCell maybe configured to follow the HARQ scheduling of TDD configuration 1because TDD configuration 1 is the TDD configuration of PCell. However,such a configuration of SCell HARQ ACK/NACK information may result insome ACK/NACK information not being fed back to eNB.

As illustrated, subframes 7 and 8 of the SCell in one radio frame couldnot be scheduled and utilized by UEs using carrier aggregation with theshown TDD configuration because PCell does not have the correspondingresources for HARQ ACK/NACK transmission. Thus, while a solution thatsubstantially reuses carrier aggregation design of release 10 may appearadvantageous, such a solution also includes several weaknesses.

FIG. 3 illustrates a diagram of HARQ ACK/NACK signal scheduling that maybe performed by processor module 152, according to embodiments. FIG. 3illustrates an issue with merely scheduling the ACK/NACK information ofSCell subframes 7 and 8 into PCell uplink subframe 3. As shown, ACK/NACKinformation of SCell subframes 9 and 0 may need to be transmitted duringa downlink subframe of PCell subframe 4 rather than during a PCelluplink subframe. Thus, the solution illustrated by FIG. 3 may leave someACK/NACK information without an uplink resource for transmission.

FIG. 4 is a flowchart illustrating a method 400 of selecting a HARQscheduling configuration that may overcome the potential downsidesillustrated in FIGS. 2 and 3, in accordance with various embodiments.

At block 404, UE 108 may establish a PCell with a first TDDconfiguration. In some embodiments, the UE 108 may establish the PCellwith the first TDD configuration based on information received in anSIB1 broadcast from a base station, e.g., eNB 104.

At block 408, UE 108 may establish an SCell communication channel with asecond TDD configuration. In some embodiments, the UE 108 may establishthe SCell with the second TDD configuration based on informationreceived, from the eNB 104, in radio resource control (RRC) signalingthrough the PCell.

At block 412, UE 108 may determine which uplink subframes are common toboth the first and second TDD configurations. These may be referred toas the common UL subframes.

At block 416, UE 108 may select a reference TDD configuration havinguplink subframes that are the same as the common UL subframes. Forexample, the uplink subframes of the selected HARQ TDD configuration maybe the same as the common uplink subframes, no more and no less.

UE 108 may determine the reference TDD configuration based oninformation shown in Table 2. Table 2 (below) shows an x-axis and ay-axis corresponding to TDD

TABLE 2 HARQ timing decision table

configurations 0-6 of the PCell and Scell, respectively. For example, ifa PCell were configured with TDD configuration 4 and an SCell wereconfigured with TDD configuration 2, UE 108 may select TDD configuration5 as the reference TDD configuration.

The cross-hatched portions of Table 2 are instances in which thereference TDD configuration is neither the TDD configuration of thePcell or the Scell.

The non-cross-hatched portions of Table 2 indicate a reference TDDconfiguration that is either the TDD configuration of the PCell or theTDD configuration of the SCell. The non-cross-hatched portions of Table2 may be described in terms of downlink subframes of the TDDconfigurations for the PCell and SCell. In embodiments, the TDDconfiguration of the PCell is selected to be the reference TDDconfiguration if the set of downlink subframes indicated by the SCellTDD configuration (e.g., SIB1 configuration) is a subset of the downlinksubframes indicated by the PCell TDD configuration (e.g., SIB1configuration). The TDD configuration of the SCell is selected to be thereference TDD configuration if the set of downlink subframes indicatedby the SCell TDD configuration is a superset of the downlink subframesindicated by the PCell TDD configuration.

Returning to FIG. 4, at block 424, UE 108 may transmit ACK/NACKinformation for the SCell according to the scheduling of the referenceTDD configuration, e.g., TDD configuration 5.

FIG. 5 schematically depicts an example of selecting a reference TDDconfiguration in accordance with various embodiments. As described abovein connection with method 400 and Table 2, box 504 encloses the uplinksubframes (2 and 3) that are common between the TDD configuration of thePCell and the TDD configuration of the SCell. Of the TDD configurationsof Table 1, TDD configuration 4 is the TDD configuration that includesuplink subframes 2 and 3. Additionally, Table 2 indicates that TDDconfiguration 4 may be used with a PCell TDD configuration 1 and anSCell TDD configuration 3. Therefore, TDD configuration 4 may beselected as the HARQ TDD configuration in this embodiment.

FIG. 6 schematically illustrates an example of HARQ signal scheduling inaccordance with various embodiments. In particular, FIG. 6 shows thatHARQ ACK/NACK information related to SCell communications may betransmitted via PCell while the SCell and PCell are configured withdifferent TDD configurations. As illustrated, SCell may be configuredwith TDD configuration 3, PCell may be configured with TDD configuration1, and HARQ ACK/NACK information related to the SCell may be sent viaPCell by using HARQ scheduling of TDD configuration 4.

FIG. 7 is a flowchart illustrating a method 700 of selecting a referenceTDD configuration in accordance with various embodiments. UE 108 mayexecute method 700 as an alternative to or in combination with method400, according to various embodiments.

At block 704, UE 108 may identify each downlink subframe of componentcarriers of both the PCell and the SCell as a type 1 subframe or a type2 subframe. UE 108 may identify a downlink subframe as a type 1 subframeif a corresponding subframe in the other component carrier is also adownlink subframe. For example, a downlink subframe of subframe 6 in thePCell component carrier may be type 1 if subframe 6 of the SCellcomponent carrier is also a downlink subframe. UE 108 may identify adownlink subframe as a type 2 subframe if a corresponding subframe inthe other component carrier is an uplink subframe. For example, ifsubframe 3 of the SCell CC is a downlink subframe and subframe 3 of thePCell CC is an uplink subframe, then subframe 3 of the SCell CC may be atype 2 downlink subframe. In other words, each downlink subframe may betype 1 if the subframe is allocated similarly as a correspondingsubframe of the other component carrier and may be type 2 if thesubframe is allocated differently than a corresponding subframe of theother component carrier.

At block 706, UE 108 may select a downlink subframe from the PCell orthe SCell.

At block 708, UE 108 may determine whether a downlink subframe istype 1. If the downlink subframe is type 1, then method 700 goes toblock 712.

At block 712, UE 108 transmits ACK/NACK signals for the selecteddownlink subframe according to a timing schedule of the TDDconfiguration of the PCell. Method 700 then returns to block 704 for thenext downlink subframe.

Returning to block 708, if the downlink subframe is not type 1, thenmethod 700 goes to either block 716 (option 1) or block 718 (option 2).

At block 716, UE 108 transmits ACK/NACK signals for the downlinksubframe according to a timing schedule of the TDD configuration of theserving cell in which the downlink subframe resides. For example, if thedownlink subframe is type 2 in the PCell, then UE 108 transmits ACK/NACKsignals for the downlink subframe according to the timing schedule ofthe TDD configuration of the PCell. If the downlink subframe is type 2in the SCell, then UE 108 transmits ACK/NACK signals for the downlinksubframe according to the timing schedule of the TDD configuration ofthe SCell. Method 700 then returns to block 704 for the next downlinksubframe.

Returning to block 708, if the downlink subframe is not type 1, thenmethod 700 may optionally go to block 718 instead of block 716.

At block 718, UE 108 may determine if the type 2 downlink subframeresides in the PCell. If the selected downlink subframe resides in thePCell, method 700 may go to block 712. If the selected downlink subframeresides in the SCell, method 700 may go to block 720.

At block 720, UE 108 may transmit ACK/NACK signals for selected subframeaccording to the HARQ-ACK timing schedule of a reference TDDconfiguration determined by method 400. Method 700 may then return toblock 704.

FIG. 8 schematically illustrates an example of an HARQ signal schedulingdiagram in accordance with various embodiments. For example, asdiscussed above in connection with method 700, downlink subframes (andspecial subframes) of the PCell and SCell may be identified as type 1,if the corresponding of the other serving cell are also downlinksubframes. Box 804 and box 808 show that subframes 0, 1, 5, and 6 ofboth the PCell and SCell may be identified as type 1. Accordingly, theHARQ ACK/NACK information of the type 1 subframes may be transmittedaccording to the TDD configuration of the PCell, e.g., TDD configuration0.

Downlink subframes of the PCell and the SCell may be identified as type2, if the corresponding subframes of the other serving cell are uplinksubframes. Subframes 3, 4, 8, and 9 of SCell include hash marks toindicate that they may be type 2 subframes. In accordance with method700, the HARQ ACK/NACK information of the type 2 subframes of the SCellmay be transmitted according to the HARQ timing of the TDD configurationof the SCell, e.g., TDD configuration 2. It may be noted that TDDconfiguration 2 would be selected either in option 1 or 2 of method 700in this instance.

FIG. 9 schematically illustrates an example of a HARQ signal schedulingdiagram in accordance with various embodiments. According to oneembodiment, downlink subframes may be identified as type 1 or type 2. Inthis embodiment, subframes 0, 1, 5, 6, and 9 of the PCell and the SCellmay be type 1 subframes, while subframe 4 of the PCell and subframes 7and 8 of the SCell may be type 2 subframes. As described in method 700,the HARQ timing of the TDD configuration of the PCell will be used forthe type 1 subframes, whether they are in the PCell or the SCell.

With respect to the type 2 subframe of the PCell, i.e., subframe 4, theHARQ ACK/NACK information may be scheduled according to the TDDconfiguration of the PCell, e.g., TDD configuration 1. This may be thecase with either option 1 or 2 of method 700.

With respect to the type 2 subframes of the SCell, i.e., subframes 7 and8, the HARQ ACK/NACK information may be feedback according to the HARQtiming of TDD configuration 3, e.g., TDD configuration of the SCell, inthe event option 1 of method 700 were used. However, if option 2 ofmethod 700 were used, the HARQ ACK/NACK information may be scheduledaccording to a HARQ TDD configuration selected according to method 400.In this instance, the HARQ TDD configuration may be TDD configuration 4,given that the PCell has a TDD configuration 1 and SCell has a TDDconfiguration 3.

The eNB 104 and UE 108 described herein may be implemented into a systemusing any suitable hardware and/or software to configure as desired.FIG. 10 illustrates, for one embodiment, an example system 1000comprising one or more processor(s) 1004, system control logic 1008coupled with at least one of the processor(s) 1004, system memory 1012coupled with system control logic 1008, non-volatile memory(NVM)/storage 1016 coupled with system control logic 1008, and a networkinterface 1020 coupled with system control logic 1008.

Processor(s) 1004 may include one or more single-core or multi-coreprocessors. Processor(s) 1004 may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, baseband processors, etc.). In anembodiment in which the system 1000 implements UE 108, processors(s)1004 may include processor module 152 and be configured to execute theembodiments of FIGS. 2-9 in accordance with various embodiments. In anembodiment in which the system 1000 implements eNB 104, processor(s)1004 may include processor module 128 and be configured to decode theHARQ ACK/NACK information transmitted by UE 108.

System control logic 1008 for one embodiment may include any suitableinterface controllers to provide for any suitable interface to at leastone of the processor(s) 1004 and/or to any suitable device or componentin communication with system control logic 1008.

System control logic 1008 for one embodiment may include one or morememory controller(s) to provide an interface to system memory 1012.System memory 1012 may be used to load and store data and/orinstructions, for example, for system 1000. System memory 1012 for oneembodiment may include any suitable volatile memory, such as suitabledynamic random access memory (DRAM), for example.

NVM/storage 1016 may include one or more tangible, non-transitorycomputer-readable media used to store data and/or instructions, forexample. NVM/storage 1016 may include any suitable non-volatile memory,such as flash memory, for example, and/or may include any suitablenon-volatile storage device(s), such as one or more hard disk drive(s)(HDD(s)), one or more compact disk (CD) drive(s), and/or one or moredigital versatile disk (DVD) drive(s), for example.

The NVM/storage 1016 may include a storage resource physically part of adevice on which the system 1000 is installed or it may be accessible by,but not necessarily a part of, the device. For example, the NVM/storage1016 may be accessed over a network via the network interface 1020.

System memory 1012 and NVM/storage 1016 may respectively include, inparticular, temporal and persistent copies of instructions 1024.Instructions 1024 may include instructions that when executed by atleast one of the processor(s) 1004 result in the system 1000implementing a one or both of methods 400 and 700 as described herein.In some embodiments, instructions 1024, or hardware, firmware, and/orsoftware components thereof, may additionally/alternatively be locatedin the system control logic 1008, the network interface 1020, and/or theprocessor(s) 1004.

Network interface 1020 may have a transceiver 1022 to provide a radiointerface for system 1000 to communicate over one or more network(s)and/or with any other suitable device. The transceiver 1022 may beimplement receiver module 144 and/or transmitter module 148. In variousembodiments, the transceiver 1022 may be integrated with othercomponents of system 1000. For example, the transceiver 1022 may includea processor of the processor(s) 1004, memory of the system memory 1012,and NVM/Storage of NVM/Storage 1016. Network interface 1020 may includeany suitable hardware and/or firmware. Network interface 1020 mayinclude a plurality of antennas to provide a multiple input, multipleoutput radio interface. Network interface 1020 for one embodiment mayinclude, for example, a network adapter, a wireless network adapter, atelephone modem, and/or a wireless modem.

For one embodiment, at least one of the processor(s) 1004 may bepackaged together with logic for one or more controller(s) of systemcontrol logic 1008. For one embodiment, at least one of the processor(s)1004 may be packaged together with logic for one or more controllers ofsystem control logic 1008 to form a System in Package (SiP). For oneembodiment, at least one of the processor(s) 1004 may be integrated onthe same die with logic for one or more controller(s) of system controllogic 1008. For one embodiment, at least one of the processor(s) 1004may be integrated on the same die with logic for one or morecontroller(s) of system control logic 1008 to form a System on Chip(SoC).

The system 1000 may further include input/output (I/O) devices 1032. TheI/O devices 1032 may include user interfaces designed to enable userinteraction with the system 1000, peripheral component interfacesdesigned to enable peripheral component interaction with the system1000, and/or sensors designed to determine environmental conditionsand/or location information related to the system 1000.

In various embodiments, the user interfaces could include, but are notlimited to, a display (e.g., a liquid crystal display, a touch screendisplay, etc.), a speaker, a microphone, one or more cameras (e.g., astill camera and/or a video camera), a flashlight (e.g., a lightemitting diode flash), and a keyboard.

In various embodiments, the peripheral component interfaces may include,but are not limited to, a non-volatile memory port, an audio jack, and apower supply interface.

In various embodiments, the sensors may include, but are not limited to,a gyro sensor, an accelerometer, a proximity sensor, an ambient lightsensor, and a positioning unit. The positioning unit may also be partof, or interact with, the network interface 1020 to communicate withcomponents of a positioning network, e.g., a global positioning system(GPS) satellite.

In various embodiments, the system 1000 may be a mobile computing devicesuch as, but not limited to, a laptop computing device, a tabletcomputing device, a netbook, a mobile phone, etc. In variousembodiments, system 1000 may have more or less components, and/ordifferent architectures.

The disclosure may include various example embodiments disclosed below.

According to various example embodiments, a method may includeestablishing, by a mobile device, a primary serving cell (PCell) and asecondary serving (SCell) with a base station. The PCell may beestablished with a first TDD configuration, and the SCell may beestablished with a second TDD configuration. The method my includereceiving, by the mobile device, downlink data through the SCell, andselecting, by the mobile device, a reference TDD configuration based onthe first and second TDD configurations. The method may includetransmitting acknowledgement information associated with the downlinkdata according to a hybrid automatic repeat request (HARD) timing of thereference TDD configuration.

In embodiments, the reference TDD configuration may be different fromthe TDD configuration indicated by a system information block of theSCell.

In embodiments, the system information block may be System InformationBlock 1 (SIB1).

In embodiments, the first TDD configuration may be indicated by SIB1 ofPCell, and

the second TDD configuration may be indicated by SIB1 of SCell.

In embodiments, the method may further include determining uplinksubframes common between the first TDD configuration and the second TDDconfiguration, and selecting the reference TDD configuration based onthe determined uplink subframes common between the first TDDconfiguration and the second TDD configuration.

In embodiments, selecting the reference TDD configuration may includeidentifying the uplink subframes common between the first TDDconfiguration and the second TDD configuration, and may includeselecting the reference TDD configuration based on a determination thatuplink subframes of the reference TDD configuration may be the same asthe common uplink subframes between the first TDD configuration and thesecond configuration.

In embodiments, selecting the reference TDD configuration may includeselecting the first TDD configuration as the reference TDD configurationif all downlink subframes of the second TDD configuration are a subsetof all downlink subframes of the first TDD configuration, and mayinclude selecting the second TDD configuration as the reference TDDconfiguration if all downlink subframes of the second TDD configurationare a superset of all downlink subframes of the first TDD configuration.

In embodiments, selecting the reference TDD configuration may includeselecting TDD DL/UL configuration 4, if the first TDD configuration isTDD DL/UL configuration 1 and the second TDD configuration is TDD DL/ULconfiguration 3; selecting TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 2 and the second TDDconfiguration is TDD DL/UL configuration 3; and selecting TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 2 and the second TDD configuration is TDD DL/ULconfiguration 4.

In embodiments, selecting the acknowledgment TDD may include selectingTDD DL/UL configuration 4, if the first TDD configuration is TDD DL/ULconfiguration 3 and the second TDD configuration is TDD DL/ULconfiguration 1; selecting TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 3 and the second TDDconfiguration is TDD DL/UL configuration 2; and selecting TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 4 and the second TDD configuration is TDD DL/ULconfiguration 2.

In embodiments, acknowledgement information may include hybrid automaticrepeat request acknowledgement (HARQ-ACK) signals, and only HARQ-ACKsignals associated with the downlink data of the SCell may betransmitted according to the HARQ timing of the reference TDDconfiguration. HARQ-ACK signals associated with downlink data of thePCell may be transmitted only according to the HARQ timing of the firstTDD configuration.

In embodiments, transmitting the acknowledgement information may includetransmitting a positive or negative acknowledgement according to theHARQ timing of the reference TDD configuration through at least oneuplink subframe.

In embodiments, each of the first, second, and reference TDDconfigurations may include at least one of TDD downlink/uplink (DL/UL)configurations 0-6 associated with release 8 of 3rd GenerationPartnership Project's long term evolution (LTE) advanced wirelesscommunication standard.

According to various example embodiments, a method may includecommunicating, by a mobile device, with a base station via first andsecond component carriers having different frequency bands and timedivision duplexing (TDD) configurations. The method may includereceiving one or more downlink transmissions via the second componentcarrier, and selecting a hybrid automatic repeat request (HARQ) timingsequence based on the TDD configurations of the first and secondcomponent carriers. The method may include transmitting one or morepositive acknowledgment and/or negative acknowledgement (ACK/NACK)signals, associated with the one or more downlink transmissions,according to the selected HARQ timing sequence.

In embodiments, selecting the HARQ timing sequence may includeidentifying, by the mobile device, each downlink subframe of the firstand second component carriers as either a first type of downlinksubframe or a second type of downlink subframe. Each downlink subframeof one of the first and second component carriers may be the first typeif a corresponding subframe of the other of the first and secondcomponent carriers is also a downlink subframe. Each downlink subframeof the one of the first and second component carriers may be the secondtype if a corresponding subframe of the other of the first and secondcomponent carriers is an uplink subframe. Selecting the HARQ timingsequence may also include selectively transmitting, by the mobiledevice, the one or more ACK/NACK signals associated with each downlinksubframe based on whether the downlink subframe is identified as thefirst type of downlink subframe or the second type of downlink subframe.

In embodiments, selectively transmitting the one or more ACK/NACKsignals may include transmitting the one or more ACK/NACK signalsaccording to the TDD configuration of the first component carrier foreach downlink subframe identified as the first type of downlinksubframe.

In embodiments, selectively transmitting the one or more ACK/NACKsignals may include transmitting the one or more ACK/NACK signalsaccording to the TDD configuration of the second component carrier foreach downlink subframe of the second component carrier identified as thesecond type of downlink subframe and transmitting the one or moreACK/NACK signals according to the TDD configuration of the firstcomponent carrier for each downlink subframe of the first componentcarrier identified as the second type of downlink subframe.

In embodiments, selectively transmitting the one or more ACK/NACKsignals may include transmitting the one or more ACK/NACK signalsaccording to a reference TDD configuration for each downlink subframe ofthe second component carrier identified as the second type andtransmitting the one or more ACK/NACK signals according to the TDDconfiguration of the first component carrier for each downlink subframeof the first component carrier identified as the second type.

In embodiments, the reference TDD configuration may be selected tocontain uplink subframes that are the same as subframes that are commonto TDD configurations of both the first and second component carriers.

In embodiments, each of the TDD configurations may include one ofconfigurations 0-6 associated with release 8 of 3rd GenerationPartnership Project's (3GPP) long term evolution (LTE) advanced wirelesscommunication standard.

In embodiments, the mobile device may be a mobile phone, a netbook, alaptop, an electronic tablet, or a data system of a vehicle.

According to various example embodiments, at least one machine readablemedium may include a number of instructions that, in response to beingexecuted on a computing device, cause the computing device to carry outany of the example embodiments of disclosed methods.

According to various example embodiments, an apparatus may include acommunication module configured to communicate with a base station viafirst and second component carriers having different frequency bands andtime division duplexing (TDD) configurations. The communication modulemay be configured to receive one or more downlink transmissions via thesecond component carrier. The apparatus may include a hybrid automaticrepeat request (HARQ) module coupled with the communication module andconfigured to select a HARQ timing sequence based on the TDDconfigurations of the first and second component carriers. The HARQmodule may be configured to generate one or more positive acknowledgmentand/or negative acknowledgement (ACK/NACK) signals, associated with theone or more downlink transmissions. The communication module may befurther configured to transmit the one or more ACK/NACK signalsaccording to the selected HARQ timing sequence.

In embodiments, the HARQ module may be further configured to identifyuplink subframes common between the TDD configurations of the first andsecond component carriers. The selected HARQ timing sequence may be aHARQ timing sequence of a reference TDD configuration having the sameuplink subframes as the identified common uplink subframes.

In embodiments, Each of the TDD configurations may include one of TDDconfigurations 0-6 associated with release 8 of 3rd GenerationPartnership Project's long term evolution (LTE) advanced wirelesscommunication standard.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the claims and theequivalents thereof.

What is claimed is:
 1. An apparatus comprising: a communication moduleto: establish communications with one or more base stations through aprimary serving cell (PCell) and a secondary serving cell (SCell), thePCell to have a first time division duplex (TDD) configuration and theSCell to have a second TDD configuration; receive downlink data throughthe SCell; and a hybrid automatic repeat request (HARQ) module to:select a reference TDD configuration based on the first and second TDDconfigurations; and transmit, via the communications module,acknowledgement information associated with the downlink data accordingto a HARQ timing of the reference TDD configuration, wherein: theacknowledgement information includes HARQ-acknowledgement (HARQ-ACK)signals; only HARQ-ACK signals associated with the downlink data of theSCell are to be transmitted according to the HARQ timing of thereference TDD configuration; and HARQ-ACK signals associated withdownlink data of the PCell are to be transmitted only according to theHARQ timing of the first TDD configuration.
 2. The apparatus of claim 1,wherein the reference TDD configuration is different from the TDDconfiguration indicated by a system information block of the SCell. 3.The apparatus of claim 2, wherein the system information block is SystemInformation Block 1 (SIB1).
 4. The apparatus of claim 1, wherein: thefirst TDD configuration is indicated by system information block (SIB1)of PCell; and the second TDD configuration is indicated by SIB1 ofSCell.
 5. The apparatus of claim 1, wherein the HARQ module is to:determine uplink subframes common between the first TDD configurationand the second TDD configuration; and select the reference TDDconfiguration based on the determined uplink subframes common betweenthe first TDD configuration and the second TDD configuration.
 6. Theapparatus of claim 5, wherein the HARQ module is to select the referenceTDD configuration by being configured to: identify the uplink subframescommon between the first TDD configuration and the second TDDconfiguration; and select the reference TDD configuration based on adetermination that uplink subframes of the reference TDD configurationare the same as the common uplink subframes between the first TDDconfiguration and the second configuration.
 7. The apparatus of claim 1,wherein the HARQ module is to select the reference TDD configuration bybeing configured to: select the first TDD configuration as the referenceTDD configuration if all downlink subframes of the second TDDconfiguration are a subset of all downlink subframes of the first TDDconfiguration; and select the second TDD configuration as the referenceTDD configuration if all downlink subframes of the second TDDconfiguration are a superset of all downlink subframes of the first TDDconfiguration.
 8. The apparatus of claim 1, wherein the HARQ module isto select the reference TDD configuration by being configured to: selectTDD DL/UL configuration 4, if the first TDD configuration is TDD DL/ULconfiguration 1 and the second TDD configuration is TDD DL/ULconfiguration 3; select TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 2 and the second TDDconfiguration is TDD DL/UL configuration 3; and select TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 2 and the second TDD configuration is TDD DL/ULconfiguration
 4. 9. The apparatus of claim 1, wherein the HARQ module isto select the reference TDD configuration by being configured to: selectTDD DL/UL configuration 4, if the first TDD configuration is TDD DL/ULconfiguration 3 and the second TDD configuration is TDD DL/ULconfiguration 1; select TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 3 and the second TDDconfiguration is TDD DL/UL configuration 2; and select TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 4 and the second TDD configuration is TDD DL/ULconfiguration
 2. 10. The apparatus of claim 1, wherein the HARQ moduleis to: transmit a positive or negative acknowledgement according to theHARQ timing of the reference TDD configuration through at least oneuplink subframe.
 11. The apparatus of claim 1, wherein each of thefirst, second, and reference TDD configurations include at least one ofTDD downlink/uplink (DL/UL) configurations 0-6 associated with release 8of 3rd Generation Partnership Project's long term evolution (LTE)advanced wireless communication standard.
 12. A method comprising:establishing, by a mobile device, communication with one or more basestations through a primary serving cell (PCell) and a secondary servingcell (SCell) with a base station, the PCell having a first time divisionduplex (TDD) configuration, the SCell having a second TDD configuration;receiving, by the mobile device, downlink data through the SCell;selecting, by the mobile device, a reference TDD configuration based onthe first and second TDD configurations; and transmittingacknowledgement information associated with the downlink data accordingto a hybrid automatic repeat request (HARQ) timing of the reference TDDconfiguration, wherein: acknowledgement information includes hybridautomatic repeat request acknowledgement (HARQ-ACK) signals; onlyHARQ-ACK signals associated with the downlink data of the SCell aretransmitted according to the HARQ timing of the reference TDDconfiguration; and HARQ-ACK signals associated with downlink data of thePCell is transmitted only according to the HARQ timing of the first TDDconfiguration.
 13. The method of claim 12, wherein the reference TDDconfiguration is different from the TDD configuration indicated by asystem information block of the SCell.
 14. The method of claim 12,wherein: the first TDD configuration is indicated by SIB1 of PCell; andthe second TDD configuration is indicated by SIB1 of SCell.
 15. Themethod of claim 12, further comprising: determining uplink subframescommon between the first TDD configuration and the second TDDconfiguration; and selecting the reference TDD configuration based onthe determined uplink subframes common between the first TDDconfiguration and the second TDD configuration. identifying the uplinksubframes common between the first TDD configuration and the second TDDconfiguration; and selecting the reference TDD configuration based on adetermination that uplink subframes of the reference TDD configurationare the same as the common uplink subframes between the first TDDconfiguration and the second configuration.
 16. The method of claim 12,wherein selecting the reference TDD configuration includes: selectingthe first TDD configuration as the reference TDD configuration if alldownlink subframes of the second TDD configuration are a subset of alldownlink subframes of the first TDD configuration; and selecting thesecond TDD configuration as the reference TDD configuration if alldownlink subframes of the second TDD configuration are a superset of alldownlink subframes of the first TDD configuration.
 17. The method ofclaim 12, wherein selecting the reference TDD configuration includes:selecting TDD DL/UL configuration 4, if the first TDD configuration isTDD DL/UL configuration 1 and the second TDD configuration is TDD DL/ULconfiguration 3; selecting TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 2 and the second TDDconfiguration is TDD DL/UL configuration 3; and selecting TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 2 and the second TDD configuration is TDD DL/ULconfiguration
 4. 18. The method of claim 12, wherein selecting theacknowledgment TDD further includes: selecting TDD DL/UL configuration4, if the first TDD configuration is TDD DL/UL configuration 3 and thesecond TDD configuration is TDD DL/UL configuration 1; selecting TDDDL/UL configuration 5, if the first TDD configuration is TDD DL/ULconfiguration 3 and the second TDD configuration is TDD DL/ULconfiguration 2; and selecting TDD DL/UL configuration 5, if the firstTDD configuration is TDD DL/UL configuration 4 and the second TDDconfiguration is TDD DL/UL configuration
 2. 19. One or morenon-transitory computer-readable media having instructions that, whenexecuted, cause a mobile device to: establish communication with one ormore base stations through a primary serving cell (PCell) and asecondary serving cell (SCell), the PCell to have a first time divisionduplex (TDD) configuration, the SCell to have a second TDDconfiguration; detect downlink data through the SCell; select areference TDD configuration based on the first and second TDDconfigurations; and transmit acknowledgement information associated withthe downlink data according to a hybrid automatic repeat request (HARQ)timing of the reference TDD configuration, wherein: acknowledgementinformation includes hybrid automatic repeat request acknowledgement(HARQ-ACK) signals; only HARQ-ACK signals associated with the downlinkdata of the SCell are transmitted according to the HARQ timing of thereference TDD configuration; and HARQ-ACK signals associated withdownlink data of the PCell is transmitted only according to the HARQtiming of the first TDD configuration.
 20. The one or morenon-transitory computer-readable media of claim 19, wherein thereference TDD configuration is different from the TDD configurationindicated by a system information block of the SCell.
 21. The one ormore non-transitory computer-readable media of claim 19, wherein theinstructions, when executed, are to cause the mobile device to: selectthe first TDD configuration as the reference TDD configuration if alldownlink subframes of the second TDD configuration are a subset of alldownlink subframes of the first TDD configuration; and select the secondTDD configuration as the reference TDD configuration if all downlinksubframes of the second TDD configuration are a superset of all downlinksubframes of the first TDD configuration.
 22. The one or morenon-transitory computer-readable media of claim 19, wherein theinstructions, when executed, are to cause the mobile device to: selectTDD DL/UL configuration 4, if the first TDD configuration is TDD DL/ULconfiguration 1 and the second TDD configuration is TDD DL/ULconfiguration 3; select TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 2 and the second TDDconfiguration is TDD DL/UL configuration 3; and select TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 2 and the second TDD configuration is TDD DL/ULconfiguration
 4. 23. The one or more non-transitory computer-readablemedia of claim 19, wherein the instructions, when executed, are to causethe mobile device to: select TDD DL/UL configuration 4, if the first TDDconfiguration is TDD DL/UL configuration 3 and the second TDDconfiguration is TDD DL/UL configuration 1; select TDD DL/ULconfiguration 5, if the first TDD configuration is TDD DL/ULconfiguration 3 and the second TDD configuration is TDD DL/ULconfiguration 2; and select TDD DL/UL configuration 5, if the first TDDconfiguration is TDD DL/UL configuration 4 and the second TDDconfiguration is TDD DL/UL configuration
 2. 24. The one or morenon-transitory computer-readable media of claim 19, wherein the mobiledevice is a mobile phone, a netbook, a laptop, an electronic tablet, ora data system of a vehicle.